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6th order bandpass ratios?


dylan117

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1 minute ago, Raptorman said:

Yes it does. I have tons of notes as well testing 20-50 at the headrest with windows down for every change ive made to my 6th. 

I have yet to see Winisd model up an accurate graph for any enclosure that I have designed/built. (I've designed over 3,000 enclosures alone)

Ported doesn't get as low as it says, it doesn't spike as hard as it says. It doesn't extend into the upper frequencies in a flat response as much as it says. It doesn't account for cabin gain, stiffness of panels within the vehicle, port areas, window configurations, box positions, etc. 

4th bandpasses are especially hilarious because a 4th that plays 20-60 completely flat in the real world has a huge freaking spike at tuning with virtually no bandwidth.

Those graphs crack me up lol

ah, ok.  As far as winisd accuracy, yeah, 4th orders are a joke. but regarding ported and parallel 6ths, while the curves in the vehicle definitely differ from the modeled curves, if you take the external factors (like the ones you listed) into account, my results have generally reflected winisd's predictions rather closely. I agree with you on all of the factors listed, they can throw things off quite a bit.  I consider winisd a useful tool for getting a rough idea of what to expect, it can be especially helpful when designing and testing multiple different enclosures in the same vehicle imo

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49 minutes ago, Raptorman said:

This has been covered already.

Post 'em up man. Would love to see the graph vs real world response! :)

Here is a series tuned box I did just to experiment with a while back.  This is the predicted response from HornResp:

HR.PNG.5a7b69e1942d1474ae7d6622aef2944f.PNG

And here is the actual measured frequency response, note that this was measured with the box out in the open, not in a vehicle:

REW.PNG.f6aa5513728ef96dab2ef058981aef92.PNG

I think the actual frequency response came out about as close as you could hope for to what HornResp predicted.  I've had similar results with ported boxes.

The hard part with any simulation software is always going to be cabin gain.  Its just too unpredictable.  If someone wants to make the effort, you can determine the cabin gain of a vehicle by measuring the frequency response of an box both in the vehicle and out in the open and then determine the difference between the two measurements.  You can then dump that info into HornResp and get a more accurate simulation, its still not perfect though and it's a big pain to do.  

 

"Nothing prevents people from knowing the truth more than the belief they already know it."
"Making bass is easy, making music is the hard part."

Builds:

U7qkMTL.jpg  LgPgE9w.jpg  Od2G3u1.jpg  xMyLoO1.jpg  9pAlXUK.jpg

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Now put it in the vehicle where it actually matters. Of course it will be accurate in an open environment.

1996 GMC Sonoma
Four Fi BTL Neo 18's In 2:1 6th Order Bandpass
2 Ampere 5k's @ .5

TEAM FI
TEAM #LITHIUMCANTDEMO

 

On 10/20/2013 at 0:37 AM, KillaCam said:

Fucking with a Prius driver is like making fun of a disabled kid. Pussies.

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2 hours ago, Raptorman said:

Now put it in the vehicle where it actually matters. Of course it will be accurate in an open environment.

Here ya go.  

This is the HornResp simulated frequency response in my Jeep with the measured cabin gain added in:

HR1.PNG.38e814ac9b756d68227af7ad1c37f9f6.PNG

 

And here is the measured response:
REW1.PNG.66b5e37334a5268c0b1fba69e9939130.PNG

 

Its not perfect, but it certainly good enough to be useful.  

"Nothing prevents people from knowing the truth more than the belief they already know it."
"Making bass is easy, making music is the hard part."

Builds:

U7qkMTL.jpg  LgPgE9w.jpg  Od2G3u1.jpg  xMyLoO1.jpg  9pAlXUK.jpg

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Yeah that looks pretty good to me. But that would require doing what you've explained. Not a realistic option for someone in my sort of business. Would work awesome for someone trying to build their personal setup though.

1996 GMC Sonoma
Four Fi BTL Neo 18's In 2:1 6th Order Bandpass
2 Ampere 5k's @ .5

TEAM FI
TEAM #LITHIUMCANTDEMO

 

On 10/20/2013 at 0:37 AM, KillaCam said:

Fucking with a Prius driver is like making fun of a disabled kid. Pussies.

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  • 3 months later...

So....it's rebuild time in my truck and I've got series tuned 6th order on my mind. I'm not REALLY concerned about ratios as I've found that there's no general rule of thumb other than try to stay 1.5:1 or above and that rear chamber is tuned lower than the front....typically an octave higher (26hz-52hz), etc. My question is more about each chambers volume. Any in site on how you determine that would be much appreciated. To give you an idea of the equipment being used is (2) Crescendo Audio Contralto 15's d2 wired down to .5ohm on a Crescendo Audio Encore 4.5k. Not really looking for anyone to design me anything. I've been doing audio for 20yrs as a hobby and have built many enclosures, but only till recently have I been trying to dabble in the 4th and 6th order designs. Thank you in advance. 

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  • 1 year later...

@Raptorman 

Go for the ratio that gives you the proper port tunings, port areas, port lengths, and chamber volumes

 

what are the proper port areas, port lengths and chamber volumes? I’m trying to design a series tuned 6th for a single zv5 12 D1 54 high side, 27 low...I saw somewhere said try to keep the front (high) port below 3” ??? but I’ve been recommended a port area that gives me a 14” long port (what I have come up with so far: 4 cubes 96 sq in (8x12) port at 54 Hz would be 14” long, 2 cubes roughly 12.25 sq in port ((was suggested 4” aero, going square 3.5x3.5)) at 27 Hz would be 19.75” long)

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